diff --git a/tryton/setup-freeze.py b/tryton/setup-freeze.py
index ddde41d8bf..4c80f4e6a0 100755
--- a/tryton/setup-freeze.py
+++ b/tryton/setup-freeze.py
@@ -119,7 +119,7 @@ if os.path.exists(ssl_paths.openssl_capath):
         (ssl_paths.openssl_capath, os.path.join('etc', 'ssl', 'certs')))
 
 version = Popen(
-    './setup.py --version', stdout=PIPE, shell=True, encoding='utf-8'
+    'python3 ./setup.py --version', stdout=PIPE, shell=True, encoding='utf-8'
     ).stdout.read()
 version = version.strip()